Natural Resources — Science STD 9 — Question

Main sources of water pollution are:

• Waste from farms i.e. fertilizers and pesticides. The chemicals in them pollute the water.
• Industries release their waste products directly into the rivers thus degrading water quality. Industries also contribute to thermal pollution as the coolants discharged by them causes a change in the average temperature of water, thereby degrading the water quality.
• Disease causing agents like bacteria, viruses and protozoans enter the sewage system. This sewage is ultimately discharged into water bodies like sea.